Selection and signaling of motion vector (MV) precisions

Abstract

An apparatus comprises: a memory; and a processor coupled to the memory and configured to: obtain a current block of a video frame, obtain candidate MVs corresponding to neighboring blocks of the video frame, the neighboring blocks neighbor the current block, obtain precisions of the candidate MVs, perform first rounding of the precisions based on a rounding scheme, perform second rounding of the candidate MVs based on the first rounding, perform pruning of the candidate MVs, and generate a candidate list based on the second rounding and the pruning.

What is claimed is: 
     
       1. A method implemented by a coding device and comprising:
 obtaining a current block of a video frame; 
 obtaining candidate motion vectors (MVs) corresponding to neighboring blocks of the current block, wherein the neighboring blocks neighbor the current block; 
 obtaining precisions of the candidate MVs; 
 performing first rounding of the precisions based on a rounding scheme, wherein the rounding scheme comprises rounding the precisions to a target precision of the current block; 
 performing second rounding of the candidate MVs based on the first rounding; 
 performing pruning of the candidate MVs; and 
 generating a candidate list based on the second rounding and the pruning. 
 
     
     
       2. The method of  claim 1 , wherein the neighboring blocks comprise a first neighboring block and a second neighboring block, and wherein the precisions comprise a first precision of the first neighboring block and a second precision of the second neighboring block. 
     
     
       3. The method of  claim 2 , wherein the rounding scheme comprises rounding the first precision to the target precision. 
     
     
       4. The method of  claim 3 , wherein the rounding scheme further comprises rounding the second precision to the target precision. 
     
     
       5. The method of  claim 1 , further comprising selecting a final candidate MV from the candidate list. 
     
     
       6. The method of  claim 5 , further comprising signaling the final candidate MV in an encoded video. 
     
     
       7. The method of  claim 6 , further comprising transmitting the encoded video. 
     
     
       8. The method of  claim 1 , wherein the pruning comprises discarding identical candidate MVs. 
     
     
       9. The method of  claim 1 , wherein the pruning comprises discarding sub-identical candidate MVs. 
     
     
       10. The method of  claim 1 , wherein the pruning comprises adding zero MVs to fill the candidate list. 
     
     
       11. An apparatus comprising:
 a memory; and 
 a processor coupled to the memory and configured to:
 obtain a current block of a video frame; 
 obtain candidate motion vectors (MVs) corresponding to neighboring blocks of the current block, wherein the neighboring blocks neighbor the current block; 
 obtain precisions of the candidate MVs; 
 perform first rounding of the precisions based on a rounding scheme, wherein the rounding scheme comprises rounding the precisions to a target precision of the current block; 
 perform second rounding of the candidate MVs based on the first rounding; 
 perform pruning of the candidate MVs; and 
 generate a candidate list based on the second rounding and the pruning. 
 
 
     
     
       12. The apparatus of  claim 11 , wherein the neighboring blocks comprise a first neighboring block and a second neighboring block, and wherein the precisions comprise a first precision of the first neighboring block and a second precision of the second neighboring block. 
     
     
       13. The apparatus of  claim 12 , wherein the rounding scheme comprises rounding the first precision to the target precision. 
     
     
       14. The apparatus of  claim 13 , wherein the rounding scheme further comprises rounding the second precision to the target precision. 
     
     
       15. The apparatus of  claim 11 , wherein the processor is further configured to select a final candidate MV from the candidate list. 
     
     
       16. The apparatus of  claim 15 , wherein the processor is further configured to signal the final candidate MV in an encoded video. 
     
     
       17. The apparatus of  claim 16 , wherein the processor is further configured to transmit the encoded video. 
     
     
       18. The apparatus of  claim 11 , wherein the pruning comprises discarding identical candidate MVs. 
     
     
       19. The apparatus of  claim 11 , wherein the pruning comprises discarding sub-identical candidate MVs. 
     
     
       20. The apparatus of  claim 11 , wherein the pruning comprises adding zero MVs to fill the candidate list. 
     
     
       21. A computer program product comprising instructions that are stored on a non-transitory computer-readable medium and that, when executed by a processor, cause an apparatus to:
 obtain a current block of a video frame; 
 obtain candidate motion vectors (MVs) corresponding to neighboring blocks of the current block, wherein the neighboring blocks neighbor the current block; 
 obtain precisions of the candidate MVs; 
 perform first rounding of the precisions based on a rounding scheme, wherein the rounding scheme comprises rounding the precisions to a target precision of the current block; 
 perform second rounding of the candidate MVs based on the first rounding; 
 perform pruning of the candidate MVs; and 
 generate a candidate list based on the second rounding and the pruning. 
 
     
     
       22. The computer program product of  claim 21 , wherein the neighboring blocks comprise a first neighboring block and a second neighboring block, wherein the precisions comprise a first precision of the first neighboring block and a second precision of the second neighboring block, and wherein the rounding scheme comprises:
 rounding the first precision to the target precision; and 
 rounding the second precision to the target precision. 
 
     
     
       23. The computer program product of  claim 21 , wherein the instructions further cause the apparatus to:
 select a final candidate MV from the candidate list; 
 signal the final candidate MV in an encoded video; and 
 transmit the encoded video. 
 
     
     
       24. The computer program product of  claim 21 , wherein the pruning comprises discarding identical candidate MVs, discarding sub-identical candidate MVs, or adding zero MVs to fill the candidate list.